Acid-reactive fillers have been widely used in dental compositions. Acid-reactive fillers include, for example, metal oxides, metal salts, and glasses. An example of an acid-reactive glass is fluoroalumuniosilicate (FAS) glass, which is a known fluoride releasing material. It is known in the art to coat or surface treat acid-reactive fillers with various substances to enhance desired properties.
For example, metal oxide powders (e.g., calcium oxide and aluminum oxide) have been coated with water-soluble high molecular weight (MW) substances to reportedly increase crushing strength, hydrophilicity, and working time, and to decrease solubility; calcium aluminum fluorosilicate glass has been treated with an acid to reportedly reduce water sensitivity and extend setting time; aluminoborate glass used in a cement has been washed with ammonium phosphate to reportedly extend the setting time of the cement; and fluoroaluminosilicate glass has been treated with silanes and/or silanols to reportedly provide cements with improved diametral tensile strength and improved fracture toughness.
For some applications, it is preferred to disperse the acid-reactive filler in a hardenable resin to form a paste. High loading levels of the acid-reactive filler in the paste (e.g., 70% by weight or higher) are often desired to provide high strength and durability of the pastes after hardening, high radiopacity, as well as high levels of fluoride release. However, loading higher levels of acid-reactive filler in the paste may result in a paste with less desirable properties (e.g., Theological properties). For example, high loadings of acid-reactive filler may result in pastes with poor handling and/or mixing characteristics (e.g., hard, dry, stringy, high viscosity, difficult to mix, and/or difficult to spread), each of which may make the use of such pastes by dental practitioners undesirable.
As such, there remains a need in the art for acid-reactive fillers with improved properties. For example, acid-reactive fillers that may be incorporated into resins at high loading levels to provide pastes, while maintaining the rheological properties typical for pastes with lower loading levels of known acid-reactive fillers (e.g., low viscosity, easily dispensed and mixed) are sought.